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Feature #11141

closed

new syntax suggestion for abbreviate definition on block parameters in order

Added by neohunter (Arnold Roa) almost 9 years ago. Updated almost 9 years ago.

Status:
Rejected
Assignee:
Target version:
-
[ruby-core:69134]

Description

One of the most commons things I do in Ruby are small block definitions:

x.each{|a| a}

One useful syntax introduced was the &:method that allows calling a method on a block if only one param is expected. It's a shortcut for a.each{|x|x.method}. I think it would be nice if Ruby had a syntax that allows me to not define the params that block would receive, but instead access them in order. For example:

x.each { $1 }

Let's suppose the block is waiting for two params, I normally do:

x.method {|a,b| a - b }

This syntax will allow us to use:

 x.method{ $1 - $2 }

So:

 x.each { p1.stg }
 x.each {|p1| p1.stg}
 x.each &:stg

would be the same.

Please consider $1 and $2 just as an example. I don't like the fact that they are global variables. It could be _1 or p1, for example:

x.method{ p1 - p2 } 
x.each{ p1 - p2 } == x.each {|p1, p2| p1 - p2 }

Or, as blocks already uses &:method it could be &:1. Or any other thing that you may consider more appropriated.

I think this syntax would be very nice for short block definitions, the downside is that it allows for bad practice on longer methods, but in the end, that's a decision that a programer should make.

Maybe this is not a valid reason, but I would like to point out that Regex is actually creating global vars as the results of match: $x vars. (for perl's historical reasons)

So why not introduce this into Ruby's syntax?

Personally I don't like either $1 nor p1. They are just the first quick things that come to my mind.

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